1. Field of the Invention
The present invention relates to obtaining tissue samples from individual seed in a high throughput efficient manner.
2. Problems in the Art
It is conventional practice in plant breeding or plant advancement experiments to grow plants from seed of known parentage. The seed are planted in experimental plots, growth chambers, greenhouses, or other growing conditions in which they are either cross-pollinated with other plants of known parentage or self-pollinated. The resulting seed are the offspring of the two parent plants or the self-pollinated plant, and are harvested, processed and planted to continue the plant breeding cycle. Specific laboratory or field-based tests may be performed on the plants, plant tissues, seed or seed tissues, in order to aid in the breeding or advancement selection process.
Generations of plants based on known crosses or self-pollinations are planted and then tested to see if these lines or varieties are moving towards characteristics that are desirable in the marketplace. Examples of desirable traits include, but are not limited to, increased yield, increased homozygoscity, improved or newly conferred resistance and/or tolerance to specific herbicides and/or pests or pathogens, increased oil content, altered starch content, neutraceutical composition, drought tolerance, and specific morphological based trait enhancements.
As can be appreciated and as is well-known in the art, these experiments can be massive in scale. They involve a huge labor force ranging from scientists to field staff to design, plant, maintain, and conduct the experiments, which can involve thousands or tens of thousands of individual plants. They also require substantial land resources. Plots or greenhouses can take up thousands of acres of land. Not only does this tie up large amounts of land for months while the plants germinate, grow, and produce seed, during which time they may be sampled for laboratory or field testing, but then the massive amounts of seed must be individual tagged, harvested, and processed.
A further complication is that much of the experimentation goes for naught. It has been reported in literature that some seed companies discard 80-90% of the plants in any generation early on in the experiment. Thus, much of the land, labor and material resources expended for growing, harvesting, and post-harvesting processing ultimately are wasted for a large percentage of the seed.
Timing pressures are also a factor. Significant advances in plant breeding have put more pressure on seed companies to more quickly advance lines or varieties of plants for more and better traits and characteristics. The plant breeders and associated workers are thus under increasing pressure to more efficiently and effectively process these generations to make more and earlier selections of plants which should be continued into the next generation of breeding.
Therefore, a movement towards early identification of traits of interest through laboratory-based seed testing has emerged. Seed is non-destructively or destructively tested to derive genetic, biochemical or phenotypic information. If traits of interest are identified, the selected seed from specific plants are used either for further experiments and advancement or to produce commercial quantities of seed. Testing seed prevents the need to grow the seed into immature plants, which are then tested. This saves time, space, and effort. If effective, early identification of desirable traits in seed can lead to greatly reducing the amount of land needed for experimental testing, the amount of seed that must be tested, and the amount of time needed to derive the information needed to advance the experiments. For example, instead of thousands of acres of planting and the subsequent handling and processing of all those plants, a fraction of acres and plants might be enough. However, because timing is still important, this is still a substantial task because even such a reduction involves processing, for example, thousands of seed per day.
A conventional method of attempting non-lethal or lethal seed sampling is as follows. Seed of interest is held for example at a sampling station. Blades, teeth or other mechanical means are used to remove a small portion from the seed. The seed portion or debris removed from the seed is collected. The seed portion or debris is transferred to another container for testing. The seed portion or debris is thus collected and ready for laboratory analysis. The existing conventional methods for performing lethal and non-lethal separation of seed tissue are a slow process. Care must be taken in the removing and handling of the seed portion or debris. Containers must then be handled and marked or otherwise tracked and identified. More importantly, the knife, teeth or mechanical means of the device used to remove a small portion of the seed must be cleaned between the sampling of each seed. There can be substantial risks of contamination by carry-over from sample to sample and in handling. Also, many times it is desirable to obtain seed material from a certain physiological tissue of the seed. For example, with corn seed, it may be desirable to take the sample from the endosperm. Or, with soybean seed, it may be desirable to take a sample from the seed opposite or away from the germ. In such cases, it is not trivial, but rather time-consuming and somewhat difficult, to orient the seed in an automated manner so as to be best positioned for removing a portion of the seed from the desired location.
As evidenced by the aforementioned example, present conventional seed analysis methods, such as is used in genetic, biochemical, or phenotypic analysis, require at least a part of the seed to be removed and processed. In removing some seed tissue, various objectives may need to be met. These may include one or more of the following objectives:
Maintain seed viability post-sampling if required.
Obtain at least a minimum required sample amount, without effecting viability.
Obtain a sample from a specific location on the seed, often requiring the ability to orient the seed in a specific position to obtain the sample.
Maintain a particular through-put level for efficiency purposes.
Reduce or virtually eliminate contamination between samples by not using the same tissue removal instrument, blade, teeth or other device to remove samples from multiple seeds.
Allow for tracking of separate samples and their correlation to other samples in a group.
Conventional seed sampling technologies do not address these requirements sufficiently, resulting in pressures on capital and labor resources, and thus illustrate the need for improvement in the state of the art. The current methods are relatively low throughput, have substantial risk of cross-contamination and tend to be inconsistent in the handling, orienting, and removal of a sample from the seed.
Therefore, a need exists in the art for apparatuses, methods and systems providing semi- and fully-automated, high throughput seed sampling.